EFFECTS OF GOMISIN-A ON THE PROMOTOR ACTION AND SERUM BILE-ACID CONCENTRATION IN HEPATOCARCINOGENESIS INDUCED BY 3'-METHYL-4-DIMETHYLAMINO-AZOBENZENE

The effects of gomisin A, a lignan component of Schizandra fruits, on the promotion stage of hepatocarcinogenesis initiated by 3'-methyl-4-d imethylamino-azobenzene (3'-MeDAB) in male Donryu rats were investigat ed. When different types of tumor promoters, phenobarbital (PB) and de oxycholic acid (DCA), were administered for 5 weeks after initiation b y 3'-MeDAB, preneoplastic alterations in the liver, determined by glut athione S-transferase placental form (GST-P), were markedly increased. Gomisin A significantly inhibited the increase in number and size of GST-P positive foci, regardless of the promotor. This lignan inhibited the increase in serum bile acid concentration by administration of DC A, but hardly influenced the serum bile acids in the PR-combined group . These results suggest that the inhibitory effect of gomisin A on the promotive action of DCA is based on improving bile acid metabolism, b ut regarding the action of PB, the effect could not be elucidated from the metabolism of bile acids.